Can someone please help me with what I am sure is a "basic" newbie question?

I have learned how to do the long-tail cast on and also have done a few rows of knit stitch. Now I am trying the purl stitch and its driving me nuts I am knitting using the English method (yarn held in right hand) and I'm not understanding the instructions when it talks about inserting the needle in the front/back of stitch?

Can someone just answer this and maybe it will help? I have just casted on using the LTCO method (see above) so this includes one row of knit stitch. I have the needle w/stitches in my left hand, right? Now: Where exactly are the casted on stitches supposed to be facing (ie: Pointing to the left, straight back or to the right?) And, does the work get placed in a different position when doing knit and a different position when doing purl?